(if using a deep pie dish, double this recipe). In a medium sized bowl, whisk together flour, sugar and salt.
Next, add the cold butter cubes to flour and, using your pastry cutter or hands, cut the butter into the flour mixture until various sized crumbs appear.
Slowly add the cold water into the flour until a ball of dough forms. Start with a ¼ cup and add more water if needed. Knead the dough quickly to bring it together. Don't worry if there is any flour left in the bowl.
Remove the dough from the bowl, round into a ball and place into a clean bowl. Cover tightly with plastic wrap and rest in the refrigerator for 45-55 minutes.
For the Sweet Potato Pie Filling
Using a hand mixer and a large bowl, whisk together sweet potato, sugar, butter, eggs, vanilla, cinnamon and nutmeg until smooth then set aside.
For the Pecan Pie Filling
In a large bowl, combine the beaten egg, pecans, both sugars, corn syrup and vanilla.
Preheat the oven to 400 degrees.
Remove dough from the fridge and add a bit of flour to a working surface or clean counter and place dough on it. Using a rolling pin, quickly roll dough out to about 1/4-1/3 inch thickness and place in your pie plate. Freeze the crust for 10 minutes.
Remove the crust from the freezer, line with parchment paper and add pie weights. Brush with egg wash (just 1 egg and 1 teaspoon of water whisked together) then Bake for 6-8 minutes or until a pale golden color.
Remove crust from the oven, reduce oven temperature to 350 degrees and place a baking sheet on the lowest oven rack.
Slowly pour sweet potato filling into the crust and carefully cover with a piece of aluminum foil.
Place the pie on the preheated baking sheet in the oven and bake for 40-45 minutes.
Remove pie from the oven and let rest (covered) for 10 minutes. Then, gently spoon the pecans over the top of the pie.
Place pie back in the oven and bake for an additional 20-25 minutes or until pie is set and the crust is golden brown.
Cool on a wire rack for 2 hours. Refrigerate overnight. Serve with whipped topping or vanilla ice cream, if desired.